Precisely positioning inserts, implants, or other medical devices, prostheses, prosthetic components, or topical application of medicines or anesthetics in or on patients' bodies depends on accurately locating structural features or anomalous structures on or within a patient's body. Continual progress has been made in the advancement and use of imaging equipment to guide the positioning of inserts, implants, or other medical devices, within patients' bodies. Noninvasive methods for locating internal structures of the body include ultrasound, X-rays, CT, and MRI equipment to locate anatomical features and anomalous structures within patients' bodies. Surgeons may use this data to create a pre-operative template to guide actions during the surgery.
The use of pre-operative images to guide the precise placement and orientation of medical devices or prosthetic components during surgery may require real-time scanning of patients' bodies or the use of robotics. Much of this requires large and expensive equipment. Alternatively, physical observation by the physician or surgeon, aided by the pre-operative scans and template, may guide placement of inserts, implants, or other medical devices, or prostheses or prosthetic components within patients' bodies.
Trialing is also critical in many implant procedures. The use of trial devices or prosthetic components provides a useful guide to the selection of the prosthetic components to be included in the chronic prosthetic implant as well as confirmation of the fit and functioning of the selected prosthetic components in vivo.
Even with templating, trialing, and advanced prosthetic components, outcomes including functional efficacy, patient comfort, and longevity of the prosthesis may not always be highly predictable, especially if procedures are performed by physicians and surgeons with different levels of skill, experience, and frequency of repeating an individual procedure. This may be confirmed by various reports in the literature that suggest a positive relationship between outcomes and the numbers of procedures performed annually by individual surgeons.